Bad reading

[chris]

When I start my V6 Alpine the temp gauge goes straight to around 105 Celsius. This problem has only been occurring for about a month. I know it can’t heat up that much in two seconds and there is no sign of over heating when I drive it. I'm guessing it’s the gauge but haven’t ruled out the sender. Anyone have any ideas?

Thanks

 

[sunbby]

Anyone have any ideas?
Thanks

I'm sure Tom will chime in, but an easy 1st check he often suggests is to swap the Fuel and Temp sender wires at the gauges. If the Fuel guage then acts the same way you know it's the sender or wiring. If the Fuel gauge acts properly (assuming it is now reading temperature) then you know it's the guage. Basically the gauges are exactly the same except for the printing on the gauge faces.

 

[MKo7144769]

I'm sure Tom will chime in, but an easy 1st check he often suggests is to swap the Fuel and Temp sender wires at the gauges. If the Fuel guage then acts the same way you know it's the sender or wiring. If the Fuel gauge acts properly (assuming it is now reading temperature) then you know it's the guage. Basically the gauges are exactly the same except for the printing on the gauge faces.

Hi, interesting information. I have a Series IV '65 Alpine and my temp gauge under normal driving conditions is hitting 200 degrees F after about 10-15 min. Is this OK or should the thermostat be changed out? What should it be reading? Thanks for any help!

 

[Bill Blue]

Hi, interesting information. I have a Series IV '65 Alpine and my temp gauge under normal driving conditions is hitting 200 degrees F after about 10-15 min. Is this OK or should the thermostat be changed out? What should it be reading? Thanks for any help!

First rule - never trust a a 40+ year old dash gauge.

Measure the temp at the water output or the radiator. I really like sticking a cooking thermometer into a cold radiator, start the engine and compare the thermometer reading to the dash gauge when you see water circulating in the radiator. I had a 20 degree difference!

Bill

 

[Paul N.]

If fuel and temperature both read wrong, don't forget the instrument voltage stabiliser behind the dash.

 

[Tom H]

Four most common causes of High temp reading on a SIII, thru SIV Alpine:
1) Voltage stabilizer stuck in the ON position. A good working original Stabilizer is a thermally actuated device that goes ON / OFF about 2 times per second providing an average output voltge of 10V (and an RMS votage of 10.8V (but that's a minor point). Modern solid state replacements put out a constant 10V, which should result in a slightly low reading, asuming all else is OK.

2) Defective sender (or wrong sender). The senders are simple thermistors, temperature dependent resistors. Thermistors are among the least stable electrical components made. If the sender is more than 10 or 15 years old it's likely shifted a lot and no longer accurate. The actual resistance and temperature variation (curve) of the sender is matched to the type of gauge. So if you use a sender that was appropriate for a Ford, for example, it's not likely a match for an Alpine gauge.

3) Defective gauge. Pretty easily verified by swaping Temp and Fuel gauges as noted by sunbby, as the temp and Fuel gauge are identical except for the dial markings.

4) Car running too hot. Best verified with an external thermometer. Could be a thermostat problem. Could be inefficient cooling. See Tiger Tom's extensive article and research on Cooling a Tiger. Much of it applies to Alpines and V6s as well.:
http://teae.org/cooling-the-tiger/

Note that the SI and SII Alpines do not use a voltage stabilizer, the Temp and Fuel senders are much different that later Series, and teh gauges are quite different from later Series- but I think still use same gauge for Temp and Fuel with diff dials.

Tom